Left panel: number of clusters as a function of ⟨ w ⟩ for the REXCESS sample (Pratt et al. 2009, PCA09) are plotted in grey. Our objects are plotted in blue and red for XMM-Newton and Chandra, respectively. The dashed line separates morphologically disturbed clusters from the rest. We plot XMM-Newton and Chandra lines using a binsize of 0.05 for clarity reasons, whereas for the histogram computation we use a binsize of 0.1. Right panel: distribution of the scaled density computed at 0.05 R₅₀₀ as a function of ⟨ w ⟩. Grey crosses show the REXCESS sample, while blue and red points represent XMM-Newton and Chandra measurements, respectively, of our sample. The black solid line is the best-fit of the REXCESS sample.